// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_BASE_NETWORK_DELEGATE_IMPL_H_
#define NET_BASE_NETWORK_DELEGATE_IMPL_H_

#include <stdint.h>

#include "base/strings/string16.h"
#include "net/base/completion_callback.h"
#include "net/base/network_delegate.h"
#include "net/cookies/canonical_cookie.h"
#include "net/proxy/proxy_retry_info.h"

class GURL;

namespace base {
class FilePath;
}

namespace net {

class CookieOptions;
class HttpRequestHeaders;
class HttpResponseHeaders;
class ProxyInfo;
class URLRequest;

class NET_EXPORT NetworkDelegateImpl : public NetworkDelegate {
public:
    ~NetworkDelegateImpl() override { }

private:
    // This is the interface for subclasses of NetworkDelegate to implement. These
    // member functions will be called by the respective public notification
    // member function, which will perform basic sanity checking.

    // Called before a request is sent. Allows the delegate to rewrite the URL
    // being fetched by modifying |new_url|. If set, the URL must be valid. The
    // reference fragment from the original URL is not automatically appended to
    // |new_url|; callers are responsible for copying the reference fragment if
    // desired.
    // |callback| and |new_url| are valid only until OnURLRequestDestroyed is
    // called for this request. Returns a net status code, generally either OK to
    // continue with the request or ERR_IO_PENDING if the result is not ready yet.
    // A status code other than OK and ERR_IO_PENDING will cancel the request and
    // report the status code as the reason.
    //
    // The default implementation returns OK (continue with request).
    int OnBeforeURLRequest(URLRequest* request,
        const CompletionCallback& callback,
        GURL* new_url) override;

    // Called right before the network transaction starts. Allows the delegate to
    // read/write |headers| before they get sent out. |callback| and |headers| are
    // valid only until OnCompleted or OnURLRequestDestroyed is called for this
    // request.
    // See OnBeforeURLRequest for return value description. Returns OK by default.
    int OnBeforeStartTransaction(URLRequest* request,
        const CompletionCallback& callback,
        HttpRequestHeaders* headers) override;

    // Called after a connection is established , and just before headers are sent
    // to the destination server (i.e., not called for HTTP CONNECT requests). For
    // non-tunneled requests using HTTP proxies, |headers| will include any
    // proxy-specific headers as well. Allows the delegate to read/write |headers|
    // before they get sent out. |headers| is valid only until OnCompleted or
    // OnURLRequestDestroyed is called for this request.
    void OnBeforeSendHeaders(URLRequest* request,
        const ProxyInfo& proxy_info,
        const ProxyRetryInfoMap& proxy_retry_info,
        HttpRequestHeaders* headers) override;

    // Called right before the HTTP request(s) are being sent to the network.
    // |headers| is only valid until OnCompleted or OnURLRequestDestroyed is
    // called for this request.
    void OnStartTransaction(URLRequest* request,
        const HttpRequestHeaders& headers) override;

    // Called for HTTP requests when the headers have been received.
    // |original_response_headers| contains the headers as received over the
    // network, these must not be modified. |override_response_headers| can be set
    // to new values, that should be considered as overriding
    // |original_response_headers|.
    // If the response is a redirect, and the Location response header value is
    // identical to |allowed_unsafe_redirect_url|, then the redirect is never
    // blocked and the reference fragment is not copied from the original URL
    // to the redirection target.
    //
    // |callback|, |original_response_headers|, and |override_response_headers|
    // are only valid until OnURLRequestDestroyed is called for this request.
    // See OnBeforeURLRequest for return value description. Returns OK by default.
    int OnHeadersReceived(
        URLRequest* request,
        const CompletionCallback& callback,
        const HttpResponseHeaders* original_response_headers,
        scoped_refptr<HttpResponseHeaders>* override_response_headers,
        GURL* allowed_unsafe_redirect_url) override;

    // Called right after a redirect response code was received.
    // |new_location| is only valid until OnURLRequestDestroyed is called for this
    // request.
    void OnBeforeRedirect(URLRequest* request, const GURL& new_location) override;

    // This corresponds to URLRequestDelegate::OnResponseStarted.
    void OnResponseStarted(URLRequest* request) override;

    // Called when bytes are received from the network, such as after receiving
    // headers or reading raw response bytes. This includes localhost requests.
    // |bytes_received| is the number of bytes measured at the application layer
    // that have been received over the network for this request since the last
    // time OnNetworkBytesReceived was called. |bytes_received| will always be
    // greater than 0.
    // Currently, this is only implemented for HTTP transactions, and
    // |bytes_received| does not include TLS overhead or TCP retransmits.
    void OnNetworkBytesReceived(URLRequest* request,
        int64_t bytes_received) override;

    // Called when bytes are sent over the network, such as when sending request
    // headers or uploading request body bytes. This includes localhost requests.
    // |bytes_sent| is the number of bytes measured at the application layer that
    // have been sent over the network for this request since the last time
    // OnNetworkBytesSent was called. |bytes_sent| will always be greater than 0.
    // Currently, this is only implemented for HTTP transactions, and |bytes_sent|
    // does not include TLS overhead or TCP retransmits.
    void OnNetworkBytesSent(URLRequest* request, int64_t bytes_sent) override;

    // Indicates that the URL request has been completed or failed.
    // |started| indicates whether the request has been started. If false,
    // some information like the socket address is not available.
    void OnCompleted(URLRequest* request, bool started) override;

    // Called when an URLRequest is being destroyed. Note that the request is
    // being deleted, so it's not safe to call any methods that may result in
    // a virtual method call.
    void OnURLRequestDestroyed(URLRequest* request) override;

    // Corresponds to ProxyResolverJSBindings::OnError.
    void OnPACScriptError(int line_number, const base::string16& error) override;

    // Called when a request receives an authentication challenge
    // specified by |auth_info|, and is unable to respond using cached
    // credentials. |callback| and |credentials| must be non-NULL, and must
    // be valid until OnURLRequestDestroyed is called for |request|.
    //
    // The following return values are allowed:
    //  - AUTH_REQUIRED_RESPONSE_NO_ACTION: |auth_info| is observed, but
    //    no action is being taken on it.
    //  - AUTH_REQUIRED_RESPONSE_SET_AUTH: |credentials| is filled in with
    //    a username and password, which should be used in a response to
    //    |auth_info|.
    //  - AUTH_REQUIRED_RESPONSE_CANCEL_AUTH: The authentication challenge
    //    should not be attempted.
    //  - AUTH_REQUIRED_RESPONSE_IO_PENDING: The action will be decided
    //    asynchronously. |callback| will be invoked when the decision is made,
    //    and one of the other AuthRequiredResponse values will be passed in with
    //    the same semantics as described above.
    AuthRequiredResponse OnAuthRequired(URLRequest* request,
        const AuthChallengeInfo& auth_info,
        const AuthCallback& callback,
        AuthCredentials* credentials) override;

    // Called when reading cookies to allow the network delegate to block access
    // to the cookie. This method will never be invoked when
    // LOAD_DO_NOT_SEND_COOKIES is specified.
    bool OnCanGetCookies(const URLRequest& request,
        const CookieList& cookie_list) override;

    // Called when a cookie is set to allow the network delegate to block access
    // to the cookie. This method will never be invoked when
    // LOAD_DO_NOT_SAVE_COOKIES is specified.
    bool OnCanSetCookie(const URLRequest& request,
        const std::string& cookie_line,
        CookieOptions* options) override;

    // Called when a file access is attempted to allow the network delegate to
    // allow or block access to the given file path.  Returns true if access is
    // allowed.
    bool OnCanAccessFile(const URLRequest& request,
        const base::FilePath& path) const override;

    // Returns true if the given |url| has to be requested over connection that
    // is not tracked by the server. Usually is false, unless user privacy
    // settings block cookies from being get or set.
    bool OnCanEnablePrivacyMode(
        const GURL& url,
        const GURL& first_party_for_cookies) const override;

    // Returns true if the embedder has enabled experimental cookie features.
    bool OnAreExperimentalCookieFeaturesEnabled() const override;

    // TODO(jww): Remove this once we ship strict secure cookies:
    // https://crbug.com/546820
    bool OnAreStrictSecureCookiesEnabled() const override;

    // Called when the |referrer_url| for requesting |target_url| during handling
    // of the |request| is does not comply with the referrer policy (e.g. a
    // secure referrer for an insecure initial target).
    // Returns true if the request should be cancelled. Otherwise, the referrer
    // header is stripped from the request.
    bool OnCancelURLRequestWithPolicyViolatingReferrerHeader(
        const URLRequest& request,
        const GURL& target_url,
        const GURL& referrer_url) const override;
};

} // namespace net

#endif // NET_BASE_NETWORK_DELEGATE_IMPL_H_
